Stenosing tenosynovitis is most commonly caused by overuse from chronic repetitive activities using the hand or the involved finger. Examples include work activities (e.g., computer use, materials handling) or recreational activities (e.g., knitting, golf, racket sports). Carpenters who use hammers suffer from this as well as those who continuously grip wood or other materials when cutting them due to having to use your hands as a clamp to hold things in place.

Primary stenosing tenosynovitis can be idiopathic, occurring in middle age women more frequently than in men, but can present also in infancy.

Secondary stenosing tenosynovitis can be caused by disease or entities that cause connective tissue disorders including the following:

- Rheumatoid arthritis and psoriatic arthritis—therefore the clinician must assess the hands for rheumatologic deformities.

- Gout

- Diabetes mellitus

- Amyloidosis

- Systemic lupus erythematosus

Others causes may include the following:

- Direct trauma to the site

- During the postpartum period

- Congenital

Several risk factors of CMC OA of the thumb are known. Each of these risk factors does not cause CMC OA by itself, but acts as a predisposing factor influencing the process of OA in some way. Risk factors include: female gender, suffering from obesity, repetitive heavy manual labor, familial predisposition and hormonal changes, such as menopause.

The cause of trigger finger is unclear but several causes have been proposed. It has also been called stenosing tenosynovitis (specifically "digital tenosynovitis stenosans"), but this may be a misnomer, as inflammation is not a predominant feature.

It has been speculated that repetitive forceful use of a digit leads to narrowing of the fibrous digital sheath in which it runs, but there is little scientific data to support this theory. The relationship of trigger finger to work activities is debatable and scientific evidence for and against hand use as a cause exist. While the mechanism is unclear, there is some evidence that triggering of the thumb is more likely to occur following surgery for carpal tunnel syndrome. It may also occur in rheumatoid arthritis.

CMC OA is the most common form of OA affecting the hand. Dahaghin et al. showed that about 15% of women and 7% of men between 50 and 60 years of age suffer from CMC OA of the thumb. However, in about 65% of people older than 55 years, radiologic evidence of OA was present without any symptoms. Armstrong et al. reported a prevalence of 33% in postmenopausal women, of which one third was symptomatic, compared to 11% in men older than 55 years. This shows CMC OA of the thumb is significantly more prevalent in women, especially in postmenopausal women, compared to men.

About 1.8 million people go to the emergency department each year due to hand injuries.

Workers in certain fields are at risk of repetitive strains. Most occupational injuries are musculoskeletal disorders, and many of these are caused by cumulative trauma rather than a single event. Miners and poultry workers, for example, must make repeated motions which can cause tendon, muscular, and skeletal injuries.

The cause of de Quervain's disease is not established. Evidence regarding a possible relation with occupational risk factors is debated. A systematic review of potential risk factors discussed in the literature did not find any evidence of a causal relationship with occupational factors. However, researchers in France found personal and work-related factors were associated with de Quervain's disease in the working population; wrist bending and movements associated with the twisting or driving of screws were the most significant of the work-related factors. Proponents of the view that De Quervain syndrome is a repetitive strain injury consider postures where the thumb is held in abduction and extension to be predisposing factors. Workers who perform rapid repetitive activities involving pinching, grasping, pulling or pushing have been considered at increased risk. Specific activities that have been postulated as potential risk factors include intensive computer mouse use, trackball use, and typing, as well as some pastimes, including bowling, golf, fly-fishing, piano-playing, sewing, and knitting.

Women are affected more often than men. The syndrome commonly occurs during and after pregnancy. Contributory factors may include hormonal changes, fluid retention and—more debatably—lifting.

Trigger fingers is a common disorder characterized by catching, snapping or locking of the involved finger flexor tendon, associated with dysfunction and pain. It is a sub-set of stenosing tenosynovitis.

A disparity in size between the flexor tendon and the surrounding retinacular pulley system, most commonly at the level of the first annular (A1) pulley, results in difficulty flexing or extending the finger and the "triggering" phenomenon. The label of trigger finger is used because when the finger unlocks, it pops back suddenly, as if releasing a trigger on a gun.

The international debate regarding the relationship between CTS and repetitive motion in work is ongoing. The Occupational Safety and Health Administration (OSHA) has adopted rules and regulations regarding cumulative trauma disorders. Occupational risk factors of repetitive tasks, force, posture, and vibration have been cited.

The relationship between work and CTS is controversial; in many locations, workers diagnosed with carpal tunnel syndrome are entitled to time off and compensation.

Some speculate that carpal tunnel syndrome is provoked by repetitive movement and manipulating activities and that the exposure can be cumulative. It has also been stated that symptoms are commonly exacerbated by forceful and repetitive use of the hand and wrists in industrial occupations, but it is unclear as to whether this refers to pain (which may not be due to carpal tunnel syndrome) or the more typical numbness symptoms.

A review of available scientific data by the National Institute for Occupational Safety and Health (NIOSH) indicated that job tasks that involve highly repetitive manual acts or specific wrist postures were associated with incidents of CTS, but causation was not established, and the distinction from work-related arm pains that are not carpal tunnel syndrome was not clear. It has been proposed that repetitive use of the arm can affect the biomechanics of the upper limb or cause damage to tissues. It has also been proposed that postural and spinal assessment along with ergonomic assessments should be included in the overall determination of the condition. Addressing these factors has been found to improve comfort in some studies. A 2010 survey by NIOSH showed that 2/3 of the 5 million carpal tunnel cases in the US that year were related to work. Women have more work-related carpal tunnel syndrome than men.

Speculation that CTS is work-related is based on claims such as CTS being found mostly in the working adult population, though evidence is lacking for this. For instance, in one recent representative series of a consecutive experience, most patients were older and not working. Based on the claimed increased incidence in the workplace, arm use is implicated, but the weight of evidence suggests that this is an inherent, genetic, slowly but inevitably progressive idiopathic peripheral mononeuropathy.

Arthritis of the hand is common in females. Osteoarthritis of the hand joints is much less common than rheumatoid arthritis. As the arthritis progresses, the finger gets deformed and lose its functions. Moreover, many patients with rheumatoid arthritis have this dysfunction present in both hands and become disabled due to chronic pain. Osteoarthritis is most common at the base of thumb and is usually treated with pain pills, splinting or steroid injections.

Carpal tunnel syndrome is a common disorder of the hand. This disorder results from compression of an important nerve in the wrist. Disorders like diabetes mellitus, thyroid or rheumatoid arthritis can narrow the tunnel and cause impingement of the nerve. Carpal tunnel syndrome also occurs in people who overuse their hand or perform repetitive actions like using a computer key board, a cashiers machine or a musical instrument. When the nerve is compressed, it can result in disabling symptoms like numbness, tingling, or pain in the middle three fingers. As the condition progresses, it can lead to muscle weakness and inability to hold objects. The pain frequently occurs at night and can even radiate to the shoulder. Even though the diagnosis is straightforward, the treatment is not satisfactory.

Dupuytren's contracture is another disorder of the fingers that is due to thickening of the underlying skin tissues of the palm. The disorder results in a deformed finger which appears thin and has small bumps on the surface. Dupuytren's contracture does run in families, but is also associated with diabetes, smoking, seizure recurrence and other vascular disorders. Dupuytren's does not need any treatment as the condition can resolve on its own. However, if finger function is compromised, then surgery may be required.

Ganglion cysts are soft globular structures that occur on the back of the hand usually near the junction of the wrist joint. These small swellings are usually painless when small but can affect hand motion when they become large. The cysts contain a jelly like substance and usually do disappear on their own. If the ganglion cyst is not bothersome, it should be left alone. Just removing the fluid from the cyst is not curative because fluid will come back in less than a week. Surgery is often done for large cysts but the results are poor. Recurrences are common, and there is always the possibility of nerve or joint damage.

Tendinitis is disorder when tendons of the hands become inflamed. Tendons are thick fibrous cords that attach small muscles of the hand to bones. A Tendon is useful for generation of power to bend or extend the finger. When repetitive action is performed, tendons often get inflamed and present with pain and difficulty for moving the finger. In most cases, tendinitis can be treated with rest, ice and wearing splints. In some cases, an injection of corticosteroid may help. Tendinitis is primarily a disorder from overuse but if not treated properly, can become chronic.

Trigger finger is a common disorder which occurs when the sheath through which tendons pass, become swollen or irritated. Initially, the finger may catch during movement but symptoms like pain, swelling and a snap may occur with time. The finger often gets locked in one position and it may be difficult to straighten or bend the finger. Trigger finger has been found to be associated with diabetes, gout and rheumatoid arthritis.

Gamekeeper's thumb and skier's thumb are two similar conditions, both of which involve insufficiency of the ulnar collateral ligament (UCL) of the thumb. The chief difference between these two conditions is that Skier's thumb is generally considered to be an acute condition acquired after a fall or similar abduction injury to the metacarpophalangeal (MCP) joint of the thumb, whereas gamekeeper's thumb typically refers to a chronic condition which has developed as a result of repeated episodes of lower-grade hyperabduction over a period of time. Gamekeeper's thumb is more difficult to treat because the UCL has lengthened and become thinner as a result of repeated injury. It is moderately painful compared to similar injuries.

In addition to skiing, this injury (resulting from forced abduction or hyperextension of the proximal phalanx of the thumb) is seen in a wide variety of other athletic endeavors. The most common mechanism of injury appears to be when a person extends the arm in an attempt to block a fall. The stress resulting from falling onto an abducted thumb produces a valgus force on the MCP joint of the thumb, resulting in a sprain or tear of the UCL.

In a recent study, 49% of UCL disruptions of the thumb were caused by a fall onto an outstretched hand. Sports injuries accounted for most of the remaining injuries, with only 2.4% acquired as a result of skiing injuries.

The Jersey Finger is a finger-related tendon injury that is common in athletics and can result in permanent loss of flexion of the end of the finger if not surgically repaired.

This injury often occurs in American football when a player grabs another player's jersey with the tips of one or more fingers while that player is pulling or running away.

Most people relieved of their carpal tunnel symptoms with conservative or surgical management find minimal residual or "nerve damage". Long-term chronic carpal tunnel syndrome (typically seen in the elderly) can result in permanent "nerve damage", i.e. irreversible numbness, muscle wasting, and weakness. Those that undergo a carpal tunnel release are nearly twice as likely as those not having surgery to develop trigger thumb in the months following the procedure.

While outcomes are generally good, certain factors can contribute to poorer results that have little to do with nerves, anatomy, or surgery type. One study showed that mental status parameters or alcohol use yields much poorer overall results of treatment.

Recurrence of carpal tunnel syndrome after successful surgery is rare.

Stenosing tenosynovitis (also known as trigger finger or trigger thumb) is a painful condition caused by the inflammation (tenosynovitis) and progressive restriction of the superficial and deep flexors fibrous tendon sheath adjacent to the A1 pulley at a metacarpal head. Repetitive forceful compression, tensile stress, and resistive flexion, causes inflammation, swelling, and microtrauma, that results in thickening (commonly a nodular formation) of the tendon distal to the pulley and stenosis of the tendon sheath leading to a painful digital base, limitation of finger movements, triggering, snapping, locking, and deformity progressively.

Patients report a popping sound at the proximal interphalangeal joint (PIP), morning stiffness with/without triggering, delayed and sometimes painful extension of the digit, and when more advanced, a locking position that requires manipulation to extend the affected finger. This condition more commonly affects the middle and ring fingers (occasionally the thumb), and the flexor rather than extensor tendons in the hand.

In rheumatic trigger finger (or in diabetes), more than one finger may be involved. Cases of stenosing peroneal tenosynovitis, have been reported where the patient presents with pain over the lateral malleolus, both with active and passive range of motion and no physical of radiographic evidence of instability.

Splinting for fingers.

Passive stretching and clearing the deformity.

Swan neck deformity has many possible causes arising from the DIP, PIP, or even the MCP joints. In all cases, there is a stretching of the volar plate at the PIP joint to allow hyperextension, plus some damage to the attachment of the extensor tendon to the base of the distal phalanx that produces a hyperflexed mallet finger. Duck bill deformity is a similar condition affecting the thumb (which cannot have true swan neck deformity because it does not have enough joints).

It is unclear whether the cause of the trigger thumb is congenital or acquired. The occurrence of bilateral incidence and trigger thumbs in both children of twins are an indication for a congenital cause. Trigger thumb in children is also associated with trisomy of chromosome 13. For these reasons it was assumed that trigger thumbs in children are to be of congenital cause. However, more and more evidence which point towards an acquired cause have been found in recent studies. Therefore the name pediatric trigger thumb is also widely used (and currently preferred by some) for the same disorder.

De Quervain syndrome involves noninflammatory thickening of the tendons and the synovial sheaths that the tendons run through. The two tendons concerned are those of the extensor pollicis brevis and abductor pollicis longus muscles. These two muscles run side by side and function to bring the thumb away from the hand; the extensor pollicis brevis brings the thumb outwards radially, and the abductor pollicis longus brings the thumb forward away from the palm. De Quervain tendinopathy affects the tendons of these muscles as they pass from the forearm into the hand via a fibro-osseous tunnel (the first dorsal compartment).

Evaluation of histopathological specimens shows a thickening and myxoid degeneration consistent with a chronic degenerative process, as opposed to inflammation. The pathology is identical in de Quervain seen in new mothers.

Gamekeeper's thumb (also known as skier's thumb or UCL tear) is a type of injury to the ulnar collateral ligament (UCL) of the thumb. The UCL may be torn, damaged or in some cases avulsed from its insertion site into the proximal phalanx of the thumb in the vast majority (approximately 90%) of cases. This condition is commonly observed among gamekeepers and Scottish fowl hunters, as well as athletes (such as volleyballers). It also occurs among people who sustain a fall onto an outstretched hand, frequently skiers.

One way to prevent this injury from occurring is to be informed and educated about the risks involved in hurting your wrist and hand. If patients do suffer from median nerve palsy, occupational therapy or wearing a splint can help reduce the pain and further damage. Wearing a dynamic splint, which pulls the thumb into opposition, will help prevent an excess in deformity. This splint can also assist in function and help the fingers flex towards the thumb. Stretching and the use of C-splints can also assist in prevention of further damage and deformity. These two methods can help in the degree of movement the thumb can have. While it is impossible to prevent trauma to your arms and wrist, patients can reduce the amount of compression by maintaining proper form during repetitive activities. Furthermore, strengthening and increasing flexibility reduces the risk of nerve compression.

The ulnar collateral ligament is an important stabilizer of the thumb. Thumb instability resulting from disruption of the UCL profoundly impairs the overall function of the involved hand. Because of this, it is critical that these injuries receive appropriate attention and treatment.

Most gamekeeper's thumb injuries are treated by simply immobilizing the joint in a thumb spica splint or a modified wrist splint and allowing the ligament to heal. However, near total or total tears of the UCL may require surgery to achieve a satisfactory repair, especially if accompanied by a Stener lesion.

Repetitive strain injury (RSI) and associative trauma orders are umbrella terms used to refer to several discrete conditions that can be associated with repetitive tasks, forceful exertions, vibrations, mechanical compression, or sustained/awkward positions. Examples of conditions that may sometimes be attributed to such causes include edema, tendinosis (or less often tendinitis), carpal tunnel syndrome, cubital tunnel syndrome, De Quervain syndrome, thoracic outlet syndrome, intersection syndrome, golfer's elbow (medial epicondylitis), tennis elbow (lateral epicondylitis), trigger finger (so-called stenosing tenosynovitis), radial tunnel syndrome, ulnar tunnel syndrome, and focal dystonia.

Since the 1970s there has been a worldwide increase in RSIs of the arms, hands, neck, and shoulder attributed to the widespread use of typewriters/computers in the workplace that require long periods of repetitive motions in a fixed posture.

The classically used Leddy and Packer Classification classifies Jersey finger tendon injuries based on the degree of tendon injury, retraction, and presence of a concomitant fracture.

Often, surgical pins are inserted into the injured digit to stabilize the bone and tendon in their proper alignment. Post surgical complications can include infection, pin failure and nail and joint deformity. Surgery is often accompanied by a rehabilitation protocol to strengthen the injured muscle and help the patient regain as much range of motion (ROM) as possible at the affected joint. The finger may never return normal extension ROM.

Nintendo thumb, also known as gamer's grip, Nintendonitis and similar names, is a video game-related health problem classified as a form of repetitive strain injury (RSI). The symptoms are the blistering, paraesthesia and swelling of the thumbs, mainly through use of the D-pad, though any finger can be affected. This can lead to stress on tendons, nerves and ligaments in the hands, and further onto lateral epicondylitis ("tennis elbow"), tendinitis, bursitis and carpal tunnel syndrome (CTS).

Some of the symptoms are described under trigger finger.

Originally known in a video gaming context as "Leather Thumb", this condition was known to occur frequently among users of 2nd generation video game consoles such as the Intellivision or the Atari 2600 in the late 1970s and early 1980s. The condition was first highlighted when the Nintendo games consoles were released, leading to reported cases of RSI, primarily in children (being one of the primary audiences of early-generation videogames). Later, the controllers for the Sony PlayStation and PlayStation 2 were noted as causing the condition. However, due to the shape, size and extended use of game controllers it is not limited to just those specific ones and can occur in users of any gamepad or joystick. Similar problems have also been observed with the use of mobile phones, and text messaging in particular (see Blackberry thumb).

The etiology of the Galeazzi fracture is thought to be a fall that causes an axial load to be placed on a hyperpronated forearm. However, researchers have been unable to reproduce the mechanism of injury in a laboratory setting.

After the injury, the fracture is subject to deforming forces including those of the brachioradialis, pronator quadratus, and thumb extensors, as well as the weight of the hand. The deforming muscular and soft-tissue injuries that are associated with this fracture cannot be controlled with plaster immobilization.